Starting Seeds Indoors

The seed packs are purchased, the starter kits stand ready, and the date is here. Plant those seeds! It can be exciting, putting the first seeds of the year into soil. It can be a little intimidating and scary too. Most of us have had problems growing seeds indoors in the past and each year we’re haunted by fears of spindly plants that won’t survive.

If you follow a proven process and take a few precautions, seeds started in your house will give you a marvelous jump start on the growing season.

Begin with clean, sterilized growing containers. If you use store-bought seed starter kits, they should already be clean enough. If you are using pots or containers from years past, wash them, then rinse them with a mild bleach solution (one part bleach to nine parts water). Fill the pots with sterile or pasteurized potting soil. Why is this cleanliness important? One of the biggest threats to young plants is Damping Off Disease (more on that later) and sterilized conditions will minimize it.

The soil in the containers should be moist and warm. Peat and most potting soils need to be wet before planting. If you put dry potting soil into a pot and then add water, not all of the soil will be moistened. Mix the soil with water in a separate container and then put the moist soil into the pots. Let the tray of peat pellets or starter pots sit for at least a day in the room you’ll have the plants in. Most seeds don’t like cold soil.

Using pre-moistened potting soil.

Follow the directions on the seed packet as to the depth of planting. Using a pencil, chopstick, or your finger, dig out a little hole in the soil to the appropriate depth. Sprinkle a few seeds in and around the hole and lightly cover them with soil. Continue doing this with each of your pots.

When you have the entire flat or group of pots planted, spray the soil surface with a mist of water. You don’t want to drown them, you want to moisten any of the surface that may have dried out.

Misting the soil surface.

After watering, cover the pots with plastic. Starter kits are nice because they have a fitted cover that matches the base. If you’re using separate pots or flats with no top, cover them with plastic bags or plastic wrap. The intent is to keep the growing environment humid. One of the easiest ways to kill germinating seeds is to let them dry out.

Covered and humid.

At some point you also want to label the pots so you know what you planted. Don’t trust your memory (I know I can’t). Drawing your seed plan on a piece of paper, marking the flats with marked tape, or using labeled popsicle sticks are just some ways to note which seeds went where. Don’t think you’ll be able to recognize the plant right away. Most seedlings look alike for the first few weeks.

Labeled with masking tape.

Set the pots in a warm, well-lit area and wait for the seedlings to emerge. You probably don’t need to water very often in the beginning. The plastic covers should keep conditions moist. If you can see condensation on the inside of the cover, the conditions should be good. Do a physical check of the soil surface at least once a day and spray a mist of water to keep it moist if there is any sign that it might be drying. You don’t want the soil to be saturated, just evenly moist.

And that’s all there is to starting seeds indoors.

Now a little about Damping Off Disease. There are a number of fungi that naturally occur in soil. When given warm, moist conditions, they grow well and can infect seeds and seedlings. Some plants are killed by a fungus before they emerge from the seed, others are assassinated after they start to sprout leaves. If you have sprouts and they disappear the next day, it’s probably Damping Off Disease. If a seedling suddenly develops a very narrow waist right at the soil line right before it dies, it’s probably Damping Off Disease.

Drier growing conditions, good air circulation, and sterile soil can all help prevent it. That’s why I suggest you avoid saturated soil and why I recommend starting with clean containers and clean soil. Air circulation becomes more important after the seedlings emerge. You can buy fungicides to spray on the soil and plants, but I find good cultural practices work well.

After the seeds are planted and watered, it’s time to wait. Have patience. Germination times vary depending on the plant and most seed packets will tell you how many days it takes the seeds to germinate. One day you’ll have brown soil and the next you’ll have little green plants popping out. That’s always exciting.

The steps after seedlings emerge are important and I’ll cover them in another article. The most important step is putting the seeds into soil. Everything else depends on that. If you haven’t yet, take a calendar and determine when you’ll put plants in your garden. Take a look at the seed packet to see when it recommends starting seeds indoors. Then work backward in your calendar and determine the day to plant seeds in your starter pots. If that day has passed, you’re late. If it is coming soon, prepare your pots and make it happen.